Preparation of a benziodazole-type iodine(III) compound and its application as a nitrating reagent for synthesis of furazans via a copper-catalyzed cascade process.

The existing hypervalent I(III) reagents bearing ONO group are limited in types and their applications primarily focused on the nitrooxylation reactions featuring a fully-exo fashion. Herein, a benziodazole-type ONO-I(III) compound was prepared and its reaction with β-monosubstituted enamines in the presence of CuI could trigger a radical nitration/cyclization/dehydration cascade to provide a series of less explored but biologically interesting furazan heterocycles. Mechanistically, the benziodazole-type ONO-I(III) compound acts as a nitrating reagent and incorporates its NO moiety into the final furazan product in a fully-endo model, a process of which was proposed to involve nitration, cyclization and dehydration.